#define _CRT_SECURE_NO_WARNINGS


#include<stdio.h>

int main()

{

	printf("Input a:");

	scanf("%d", &a)

		if (a % 5 == 0 && a % 7 == 0)

			printf("yes\n");

		else

			printf("no\n");

	return 0;

}

#include <stdio.h>

int main()

{

    int x;

    float y;

    scanf("%d", x);

    if (x <= 0)

        y = 0;

    else

        if (x > 0 && <= 10)

            y = x;

        else

            if (x >= 10 && x <= 20)

                y = 10;

            else

                if (x > 20 && x < 40)

                    y = -0.5 * x + 20;

                else y = -1;

    if (y != -1)printf("%f", y);

    else

        printf("error\n");

}

#include <stdio.h>

 int main()

{

int x;

float y;

scanf("%d",x);

    if(x<=0) 

     y=0;

else

     if(x>0&&<=10)

       y=x;

else

   if(x>=10&&x<=20)

     y=10;

else

      if(x>20&&x<40)

     y=-0.5*x+20;

  else y=-1;

      if(y!=-1)printf("%f",y);

  else

       printf("error\n");

}

#include<stdio.h>



 int main()



 {



     int s = 0, i = 1;



     while (i < 100)



     {



         s += i;



         i += 2;



     }



     printf("s=%d\n", s);



     return 0;



 }







#include<stdio.h>



 int main()



 {



     int s = 0, i = 1;



     do



     {



         s += i;



         i += 2;



     } while (i < 100);



     printf("s=%d\n", s);



     return 0;



 }







#include<stdio.h>



 int main()



 {



     int s = 0, i;



     for (i = 1; i < 100; i += 2)



         s += i;



     printf("s=%d\n", s);



     return 0;



 }

#include<stdio.h>



 int main()



 {



     int s = 0, x, i = 5;



     scanf("%d", &x);



     if (x > 0)



     {
         while (i <= 4 * x + 1)



         {



             s += i;



             i += 4;



         }



         printf("s=%d\n", s);



     }



     else



         printf("errors\n");



     return 0;



 }

#include<stdio.h>

 int main()

 {

     int i, n;

     float s = 0;

     scanf("%d", &n);

     for (i = 1; i <= n; i++)

         s += 1 / i;

     printf("s=%d", s);

     return 0;

 }